Buddy diving on their computer
- Thread starter sail-fish
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
rdolmat
Registered
ligersandtions
Contributor
Please tell me that whatever equipment of her dad's you're using includes an SPG, bottom timer, and depth gauge. If it does not include all three of these items, you really should get whatever you're missing before you make another dive.
Assuming you have all three of the above items, just plan your dives according to dive tables. You can have plenty of fun, even if you are assuming square profiles....and it will force you to be a thinking diver, rather than one who blindly relies on what a computer spits out at you.
Assuming you have all three of the above items, just plan your dives according to dive tables. You can have plenty of fun, even if you are assuming square profiles....and it will force you to be a thinking diver, rather than one who blindly relies on what a computer spits out at you.
rstofer
Contributor
Get a cheap 300m rated wrist watch with adjustable bezel for the dive timer. Or, you could use the stopwatch function if it has one. Then make sure you have a depth gauge with a max depth needle. That's all you need.
Write all of the Adjusted NDLs on a slate before the dive. Now, as you dive, you can check and see how much time you have for your maximum depth.
The problem with square profiles is that you will run out of NDL before your GF with her computer. That's the way it goes!.
Richard
Write all of the Adjusted NDLs on a slate before the dive. Now, as you dive, you can check and see how much time you have for your maximum depth.
The problem with square profiles is that you will run out of NDL before your GF with her computer. That's the way it goes!.
Richard
Last edited:
Blackwood
Contributor
FWIW, I don't have issues with two divers using one computer/depth gauge. That's what our team plans for in the event of a failure.
However, I wouldn't recommend it to new divers who haven't yet honed their buoyancy and (in particular) team skills.
However, I wouldn't recommend it to new divers who haven't yet honed their buoyancy and (in particular) team skills.
GrumpyOldGuy
Contributor
Use the tables.
The reason is the tables have a huge number of safety margins built it to compensate for imprecise data (time and depth) from manual observation. These include all the rounding rules, etc... This gives you some grace if you are sharing instruments and are a few feet below your buddy.
Computers make calculations with more precision, this also removed some of the safety margin. This works well in most cases (the extra prcision translates to increased accuracy) but is relying on more accurate depth and time (which you don't have since you are sharing). So the results can be misleading and dangerous if you approach NDL.
The reason is the tables have a huge number of safety margins built it to compensate for imprecise data (time and depth) from manual observation. These include all the rounding rules, etc... This gives you some grace if you are sharing instruments and are a few feet below your buddy.
Computers make calculations with more precision, this also removed some of the safety margin. This works well in most cases (the extra prcision translates to increased accuracy) but is relying on more accurate depth and time (which you don't have since you are sharing). So the results can be misleading and dangerous if you approach NDL.
In my opinion the key point here is the word 'failure'. You are training and planning for contingencies. To monitor ascent rates, stop times etc having one working one computer is better than having none. I can not see the value, reason or safe diving practice in planning a dive or series of dives with only one computer between a buddy team.
Hence your next part about practicing team skills.
The OP has two basic questions I believe -- the First one concerns the fact that he has determined he uses more gas than his GF. All I can say is "Welcome to the club." You will find that almost all males use more gas than females -- assuming relatively equal diving skills. You just have to get used to it and then plan your dive times based on your consumption rate. This is one reason why I dive an HP130 and my wife dives an LP95 -- and we come out just about even at the end of a normal dive.
The other question is the one to which most (every?) person has replied, "Don't rely on your GF's computer, use the tables." Which, of course, IS the "correct" answer and perhaps the safest answer. However, perhaps a touch of reality is also needed....
Someone wrote:
The OP says he generally stays from 1/2 to 1 meter below his GF (note to OP -- learn to stay even with your buddy because it makes YOU a better buddy since it is much easier to see your buddy if she is next to you rather than above you). Do any of you really believe the various Decompression algorithms are really that accurate that a 1 meter difference in depth is important? Yes, IF the OP continues to do his NDL "planning" using his GF's computer, he really needs to stay even, or above, her to make sure that his deco obligation is close to hers.
I'm NOT saying the OP should do his dives relying on his GF's computer. I am saying that there are thousands of dives every day that go off without a hitch with the "ducklings" following a DM and relying on HIS computer or knowledge.
OP -- you are a certified diver -- be a thinking diver and dive safely.
The other question is the one to which most (every?) person has replied, "Don't rely on your GF's computer, use the tables." Which, of course, IS the "correct" answer and perhaps the safest answer. However, perhaps a touch of reality is also needed....
Someone wrote:
Come on -- The "science" of Decompression is no where close to being that precise -- or as one SB member has as his sig line -- Decompression Theory is measuring with a micrometer, marking with chalk and cutting with an ax.
The OP says he generally stays from 1/2 to 1 meter below his GF (note to OP -- learn to stay even with your buddy because it makes YOU a better buddy since it is much easier to see your buddy if she is next to you rather than above you). Do any of you really believe the various Decompression algorithms are really that accurate that a 1 meter difference in depth is important? Yes, IF the OP continues to do his NDL "planning" using his GF's computer, he really needs to stay even, or above, her to make sure that his deco obligation is close to hers.
I'm NOT saying the OP should do his dives relying on his GF's computer. I am saying that there are thousands of dives every day that go off without a hitch with the "ducklings" following a DM and relying on HIS computer or knowledge.
OP -- you are a certified diver -- be a thinking diver and dive safely.
ShakaZulu
Contributor
He can really only use the tables if he knows what he's dive profile is going to be, otherwise he will have to use all those other averaging tricks, and then the dive becomes a math class. Get a computer and enjoy your diving, you are a recreational diver right?
Everything above makes sense to me.
I just have afe questions.
If your air consumption is heavier than hers, why are you diving deeper? What depths are you going to? At 12 meters you have 147 min. At 18 you have 56. If you're diving to 30m, then the issue is much more critical. She's (hopefully) planning a multi-level dive and using the computer as a secondary instrument to track her real time NDLs. You are putting yourself at risk if you're pushing the limits and just trusting her computer while she's at a shallower depth.
You can always plan your multi-level on the wheel or the new spanking ERDPml. They're cheaper than a computer, and if you have a time piece and a depth gauge, chances are (as a beginner) air will be the determining factor before NDLs.
Play it safe. People get "hits" even when they dive exactly to the tables/computers. What's that much more interesting 1.5 m below her, anyway?
I just have afe questions.
If your air consumption is heavier than hers, why are you diving deeper? What depths are you going to? At 12 meters you have 147 min. At 18 you have 56. If you're diving to 30m, then the issue is much more critical. She's (hopefully) planning a multi-level dive and using the computer as a secondary instrument to track her real time NDLs. You are putting yourself at risk if you're pushing the limits and just trusting her computer while she's at a shallower depth.
You can always plan your multi-level on the wheel or the new spanking ERDPml. They're cheaper than a computer, and if you have a time piece and a depth gauge, chances are (as a beginner) air will be the determining factor before NDLs.
Play it safe. People get "hits" even when they dive exactly to the tables/computers. What's that much more interesting 1.5 m below her, anyway?
Similar threads
